Systematics, Phylogeography, and Evolution of New World Ampullariids 

Left to Right: Pomacea guyanensis  from Belem, Brazil, P. guyanensis eggs in Belem, P. insularum from the Paraquay river, P. insularum and eggs from Fazenda Jatoba. Photos by K. Hayes.

My dissertation research integrates themes from invasion biology, systematics, phylogeography, and the evolution of Neotropical biodiversity using a group of freshwater snails in the family Ampullariidae. The information garnered from each of these areas independently will provide much needed data on ampullariids.  At the same time, this multi-disciplinary approach will not only provide a fuller understanding of these snails, but also gives insights into the evolution of Neotropical freshwater biota. The results will give pest management practitioners a better understanding of invasive ampullariids, which will be beneficial in controlling their spread.  Using invasive ampullariids as a model may also lead to generalizations applicable to other invasive species.

Testing phylogenetic hypotheses of species relationships among the genus Pomacea using modern concepts of intra-specific variation and modern techniques of molecular analysis will be an important step forward in the basic understanding of the systematics of this major group of poorly understood freshwater snails.  In a broader sense this research will provide a phylogenetic basis for testing hypotheses of the evolution of freshwater biodiversity in the Neotropics. More practically, taxonomic uncertainty casts doubt on the reliability of names used in ecological, physiological, biomedical, behavioral, and invasive species studies on the group.  Comparison among studies is unreliable.  The problems are compounded where geographic source information is lacking, as for alien populations in South-East Asia and elsewhere.  Clarifying basic taxonomy would resolve the profound, long-standing confusion among pest management practitioners and others involved in regulating these invasive species.

Clarifying the identity, geographic origins, and phylogeographic relationships of Pomacea species, particularly those in the canaliculata complex, is crucial to developing effective measures to control and prevent the spread of these pest species in the future. Furthermore, to gain a better understanding of the evolution of the group, these taxa need to be placed into a larger phylogenetic framework that includes all species groups within Pomacea. To this end, molecular genetic approaches, primarily mitochondrial and nuclear DNA sequence analyses, will be used to elucidate the phylogenetic relationships among all extant species of Pomacea and closely related outgroups (i.e. Marisa spp., Pila spp.). This phylogenetic framework will then be used to determine the geographic origins and identities of pest species in South-East Asia, Hawaii, Texas, and Florida. Characterization of genetic variation among and within South-East Asian introduced populations will also be carried out and this variation compared to that of native source populations. Finally, molecular and morphological data from ampullariids, in conjunction with geological and historical climatic data from South America, will be used to investigate models of evolutionary diversification that incorporate the long and complex history of the continent's landscape and river systems.

Left to Right: P. canaliculata eggs on taro in  Waipio Valley, Hawaii, P. canaliculata mating, P. canaliculata eggs on a water intake filter for a taro patch. Photos by K. Hayes.

Publications on Ampullariids

Hayes, K. A., R. C. Joshi, S. C. Thiengo and R. H. Cowie. In Prep. Out of South America: Multiple origins of non-native apple snails in SE Asia .

Rawlings, T. A., Hayes, K. A., Cowie, R. H. and Collins, T. M. 2007 The identity, distribution, and impacts of non-native apple snails in the Continental United States. BMC Evolutionary Biology 7:97. (Full text at BMC)

Cowie, R. H., K. A. Hayes, and S. C. Thiengo. 2006 What are apple snails? Confused taxonomy and some preliminary resolution In: Global advances in ecology and management of golden apple snails, (ed. R.C. Joshi & L.C. Sebastian), p. 3-23. Philippine Rice Research Institute, Muñoz, Nueva Ecija. (Link)

Cowie, R. H. and K. A. Hayes. 2005. Invasive ampullariid snails: taxonomic confusion and some preliminary resolution based on DNA sequences. In: Chang, Y.-F. and Lai, P.-Y., eds. Proceedings of the Asia-Pacific Economic Cooperation meeting on the management of the golden apple snail, National Pingtung University of Science and Technology, Pingtung, Taiwan, September 6-11, 2004. Pingtung: National Pingtung University of Science and Technology.

Cowie, R. H., K. A. Hayes and C. T. Tran. In Press. Distribution of the invasive apple snail Pomacea canaliculata (Lamarck) in the Hawaiian Islands (Gastropoda: Ampullariidae). Bishop Museum Occasional Papers.